Repeated Sprint Test Research Articles

Anaerobic Capacity Level Differences of Each Player Position in Volleyball

Volleyball is one of the most popular sports in the world. To be a professional volleyball player, a coach needs to know how to train their athletes. According to the physiological component, the most used energy of a volleyball player comes from ATP-PC and glycolysis. This study aimed to classify an anaerobic capacity standard of male volleyball athletes in Indonesia. In this study, 60 athletes participated in 2 levels: Junior 15-17-year-old High School student level and 18-25-year-old University student level. The samples were chosen according to their achievement in national-level competitions in the last few years. The measurement used the Running Anaerobic Sprint Test, Vertical Jump Test, and 5-Meter Multiple Shuttle Repeat Sprint Test. The analysis employed an ANOVA test using SPSS 16 and Tukey post hoc test. This study found differences in several anaerobic performance aspects of each position in the same level of competition and at the different levels of competition. In the junior-level athletes, a significant difference was found in the average power between outside hitter and libero, peak power vertical jump between middle blocker and libero, and total distance achieved among outside hitter, opposite hitter, and setter. Senior-level athletes showed a significance different in maximum power, average power, and fatigue index of outside hitters, middle blocker, opposite hitters, setter, and libero, peak power of vertical jump among hitters, setter, and libero, and total distance achieved by hitters, setter, and libero. In conclusion, senior-level athletes showed superiority shown by higher scores of anaerobic capacity than junior-level athletes. It is suggested to conduct more research on the characteristics of each position in volleyball to train athletes more effectively and efficiently according to their position.

Exploring interactions between maturity status and playing time with fluctuations in physical fitness and hormonal markers in youth soccer players

The purpose of this study was to determine the differences in functional capacities and hormonal indices according to biological maturity and seasonal playing time status in young soccer players. Twenty-three male under-15 players (14.6 ± 0.2 years) were divided into two groups, based on their maturity status and seasonal playing time. They were measured for anthropometrics, Yo-Yo intermittent recovery level 1 (YYIR1), seven repeated sprint test (7RST), countermovement jump (CMJ), skeletal age, growth hormone, and insulin-like growth factor-1 (IGF-1) level. Age at peak height velocity (APHV) was determined to estimate the maturity timing. The results revealed that players who advanced in maturation were significantly heavier (p = 0.029) and had higher values in skeletal age (p < 0.001), sitting height (p = 0.005), CMJ (p = 0.038), and IGF-1 (p = 0.013). Players given greater playing time exhibited significantly lower fatigue index (p = 0.012), but higher CMJ (p = 0.003) and IGF-1 (p = 0.001) values. The overall results highlighted that early-maturing players and players with greater playing time obtained higher values in both CMJ and IGF-1. The findings may provide an insight on the coaches’ evaluation of players and on the possible factors that may affect the future playing status of young male soccer players.

Effects of Oral Creatine Supplementation on Power Output during Repeated Treadmill Sprinting.

The aim of the present study was to examine the effects of creatine (Cr) supplementation on power output during repeated sprints on a non-motorized treadmill. Sixteen recreationally active males volunteered for this study (age 25.5 ± 4.8 y, height 179 ± 5 cm, body mass 74.8 ± 6.8 kg). All participants received placebo supplementation (75 mg of glucose·kg−1·day−1) for 5 days and then performed a baseline repeated sprints test (6 × 10 s sprints on a non-motorised treadmill). Thereafter, they were randomly assigned into a Cr (75 mg of Cr monohydrate·kg−1·day−1) or placebo supplementation, as above, and the repeated sprints test was repeated. After Cr supplementation, body mass was increased by 0.99 ± 0.83 kg (p = 0.007), peak power output and peak running speed remained unchanged throughout the test in both groups, while the mean power output and mean running speed during the last 5 s of the sprints increased by 4.5% (p = 0.005) and 4.2% to 7.0%, respectively, during the last three sprints (p = 0.005 to 0.001). The reduction in speed within each sprint was also blunted by 16.2% (p = 0.003) following Cr supplementation. Plasma ammonia decreased by 20.1% (p = 0.037) after Cr supplementation, despite the increase in performance. VO2 and blood lactate during the repeated sprints test remained unchanged after supplementation, suggesting no alteration of aerobic or glycolytic contribution to adenosine triphosphate production. In conclusion, Cr supplementation improved the mean power and speed in the second half of a repeated sprint running protocol, despite the increased body mass. This improvement was due to the higher power output and running speed in the last 5 s of each 10 s sprint.

Preconditioning Effects of Photobiomodulation on Repeated-Sprint Ability of Professional Basketball Players.

Giovanini, B, Altimari, LR, de Paula Ramos, S, Alves Okazaki, VH, Okuno, NM, and Junior, AF. Preconditioning effects of photobiomodulation on repeated-sprint ability of professional basketball players. J Strength Cond Res 37(1): 224-229, 2023-The purpose of this study was to investigate the preconditioning effects of photobiomodulation on repeated-sprint ability of professional basketball players. Ten professional basketball players took part in this randomized, double-blind, placebo-controlled, crossover study. The subjects attended 2 repeated-sprint test sessions. In each session, the subjects performed a general warm-up, followed by a familiarization sprint. Afterward, the subjects received either the photobiomodulation (660 and 850 nm, 12 J·cm-2, 83.4 J per point, 10 points, light-emitting diode [LED] treatment) or placebo intervention and performed the repeated-sprint test. The repeated-sprint test consisted of ten 30-m sprints with 1 change of direction (15 + 15 m), interspersed by 30 seconds of passive recovery. Sprint times and heart rate responses were monitored during the test. To compare moments and conditions, linear mixed-effects models were applied with statistical significance set at p < 0.05, and Cohen's d was used as effect size (ES). The LED treatment could not improve total time (p = 0.662; ES = -0.06), best time (p = 0.869; ES = 0.02), fatigue index (p = 0.169; ES = 0.64), or sprint decrement (p = 0.124; ES = -0.75) when compared with the placebo condition. In addition, mean heart rate (p = 0.687; ES = 0.07) and maximal heart rate (p = 0.837; ES = -0.03) were similar between conditions. We concluded that the LED condition could not improve the repeated-sprint ability of professional basketball players.

Muscular and cardiorespiratory parameters of Brazilian professional futsal players: comparison between top national and regional level athletes

Aim: To compare muscular and cardiorespiratory parameters between Brazilian professional futsal athletes from different competitive levels (national versus regional). A secondary aim was to explore the correlation of physical fitness variables between both competitive levels. Methods: Twenty-two futsal players (24.7 ± 3.7 years), 11 from a regional team and 11 from a national team, were evaluated with countermovement jump test (lower limbs muscle power), square test (the speed with change direction), RSSA (anaerobic power), and YOYOIR1 (aerobic power). Tests were performed in the middle of the season for both teams. Results: The speed with change direction (p = 0.001) and mean anaerobic power (p = 0.04) were higher for national than the regional players. Sprint performance decreased similarly for national and regional level players (p < 0.001), but the latter had poorer performance (p = 0.044). From the fourth sprint on, sprints for the national level players were slower than the first three, while for the regional level players, each sprint speed was slower than the subsequent. A significant correlation was found between anaerobic power with jump height (r = −0.50; p = 0.01), speed with change direction (r=0.65; p = 0.001) and distance covered in the YOYOIR1 (r = −0.54; p = 0.01). Conclusion: National-level athletes were more agile and presented a higher mean anaerobic power than regional ones. Moreover, national-level athletes presented better performance along with repeated sprint tests, maintaining this performance for a longer time during the test.

Ten-minute warm-up in hot climate best assists thermal comfort, muscular power output, and fatigue, during soccer-specific repeated-sprint ability.

Structuring warm-up (WU) in hot climate conditions before high-intensity efforts is still drawing the attention of researchers and practitioners. The present study investigates the effect of two WU durations (i.e.10 min: WU10 and 20 min: WU20) in a hot climate (~31°C), on thermal comfort, muscular power output and fatigue after a repeated-sprint test (RSA) in soccer players. Twelve amateur soccer players (age = 21.13 ± 1.8 years; height = 172.5 ± 4.6 cm and weight = 70.8 ± 5.1 kg) participated in a cross-over randomized study, and they underwent a soccer-specific RSA test, after two WU durations and on different days. Peak power (PP), mean power (MP) and the fatigue index (FI) were calculated and analysed. Likewise, thermal comfort/discomfort (TC), tympanic temperature (Ttym) and rating of perceived exertion (RPE) were recorded at rest, after WU and after RSA. The ANOVA showed a significant increase in MP after WU10 in comparison to WU20 by 1.9%, while PP remained similar between the two durations. A significant decline in muscular power in WU20 compared to WU10 appeared from the 5th sprinting repetition and continued to the end of the RSA. The WU20, compared to the WU10, produced higher RPE at post-WU (p < 0.001) and post-RSA (p = 0.018), and higher thermal discomfort sensation in both post-WU (p = 0.022) and post-RSA (p = 0.007) point of measures. Larger increases in Ttym were recorded after WU20 compared to WU10. WU10 in a hot climate (~31°C) best assists mean power output during soccer RSA, but not peak power. Extending the WU duration up to 20 min in a hot climate was revealed to be detrimental for muscular power output, inducing excessive thermal discomfort and fatigue. Therefore, it is important that trainers and soccer players carefully consider WU duration prior to competitions and training sessions in a hot climate, to optimize physiological responses.

Performance, physiological and perceptual responses to repeated sprint tests in basketball players

Performance, physiological and perceptual responses to repeated sprint tests in basketball players

The Relationship Between Repeated Sprint Performances and 50m and 100m Swimming Degrees of Swimmers

Aim: The aim of this study is to investigate the relationship between short distance swimming performance and repeated sprint ability in swimmers. Methods: 12 male swimmers between the ages of 14-18 from Denizli Pamukkale University Swimming Sports Club Performance team voluntarily participated at this study. Freestyle swimming time of the subjects was measured by using Casio stopwatch. 10x15-m, 50-m and 100-m freestyle swimming degrees of swimmers were recorded. The ideal sprint time (IS), the total sprint time (TS) and the performance decrement (PD) were determined after repeated sprint test (RST). Lactate levels were recorded at the end of each test. The Borg scale was used to determine the perceived difficulty level. For the statistical analysis Pearson’s correlation was used to determine the correlations between 50- m and100-m freestyle swimming time and swimming times obtained at the end of RST (IS, TS, PD). Results: Significant relationships were found between the 50-m and 100-m swimming performance (p&lt;0.01). Significant correlations were found between the IS and the TS and the 50-m swim results (p&lt;0.01) and also the 100-m swim results (p&lt;0.05). Significant correlations were found between the 50-m lactate values and 100-m lactate values (p&lt;0.05). Significant relationships were found between 10x15-m RST lactate values and 50-m lactate values (p&lt;0.05). Moreover, strong relations were found between the 10x15-m RST lactate values and 100-m lactate values (p&lt;0.01). Conclusion: This study has shown that repeated sprint ability as well as higher anaerobic capability as reflected by the short distance. Keywords: swimming, repeated sprint ability, short distance swimming performance

Comparison of Ergogenic Effects of Caffeine and Nitrate Supplementation on Speed, Power and Repeated Sprint Performance of Soccer Players

Caffeine and nitrates have both been reported to enhance performance in power efforts; however, it is not clear which supplement is most effective. The aim of this study was to compare the effects of caffeine and nitrates on the performance of semi-professional soccer players during different fitness tests. Ten male soccer players in a randomized crossover design were assigned to receive caffeine (5 mg/kg body mass) (CG), nitrate ((250 mL/150 mg of NO3−) (NG), or a placebo (PG) on three different occasions. In each treatment, the participants performed the following tests: 10 m and 30 m sprints, the Illinois agility test, a countermovement jump test, a squat jump test, and a repeated sprint test (6 × 40 m). Caffeine boosted performance in jumps (CMJ: CGvsPG, p = 0.018; SJ: CGvsPG, p = 0.045 and CGvsNG, p = 0.001) and limited the decrease in performance in the RSA test (CGvsPG, p = 0.012). Nitrates limited the decrease in performance in the RSA test (NGvsPG, p = 0.035). In conclusion, the two supplements limited the decrease in performance in the test of repeated sprints, with caffeine showing a greater effect. Among the other tests, only caffeine improved performance, and only in the jumps. Thus, we can conclude that supplementation with caffeine 1 h before these kinds of activities at a dosage of 5 mg/kg of body weight can enhance performance.

Construct Validity and Reliability of a New Basketball Multidirectional Reactive Repeated Sprint Test.

The objective of this study was to investigate the construct validity and reliability of a new reactive multidirectional repeated sprinting test (RRSA5COD) in basketball players. Forty male basketball players were divided into two groups: Professional (PRO; n = 20) and Semi-professional (SEMI; n = 20). Participants completed the yo-yo intermittent recovery test level 1 (Yo-YoIR1), the squat jump (SJ), the counter movement jump (CMJ), the single leg drop jump (DJ), the 20-m sprint test, the planed multidirectional repeated sprinting test (PRSA5COD), and the RRSA5COD test. Reaction time (RT) and movement time (MT), total time (TT), best time (BT), and fatigue index (FI) were assessed. Heart rate (HR) was continuously recorded, while rating of perceived exertion (RPE) and blood lactate concentration (LA) were measured post-tests. The reliability of the RRSA5COD test was also assessed between two attempts with one week between them. The RRSA5COD results demonstrated to be reliable with most of the variables showing ICC > 0.80. BA Bonferroni post hoc revealed a significant better TT in favor of RRSA5COD (p < 0.001; ES = 0.15; small), and in favor of PRO (p < 0.001; ES = 0.006; small). The result showed a significant better performance in favor of PRO in all physical fitness tests. In conclusion, it was found that the RRSA5COD discriminates between professional and semi-professional male basketball players, and the results were demonstrated to be reliable.

The Relationship Between Repeated Sprint Performances and 50m and 100m Swimming Degrees of Swimmers

The aim of this study is to investigate the relationship between short distance swimming performance and repeated sprint ability in swimmers. 12 male swimmers between the ages of 14-18 from Denizli Pamukkale University Swimming Sports Club Performance team voluntarily participated at this study. Freestyle swimming time of the subjects was measured by using Casio stopwatch. 10x15-m, 50-m and 100-m freestyle swimming degrees of swimmers were recorded. The ideal sprint time (IS), the total sprint time (TS) and the performance decrement (PD) were determined after repeated sprint test (RST). Lactate levels were recorded at the end of each test. The Borg scale was used to determine the perceived difficulty level. For the statistical analysis Pearson’s correlation was used to determine the correlations between 50- m and100-m freestyle swimming time and swimming times obtained at the end of RST (IS, TS, PD). Significant relationships were found between the 50-m and 100-m swimming performance (p&lt;0.01). Significant correlations were found between the IS and the TS and the 50-m swim results (p&lt;0.01) and also the 100-m swim results (p&lt;0.05). Significant correlations were found between the 50-m lactate values and 100-m lactate values (p&lt;0.05). Significant relationships were found between 10x15-m RST lactate values and 50-m lactate values (p&lt;0.05). Moreover, strong relations were found between the 10x15-m RST lactate values and 100-m lactate values (p&lt;0.01). In conclusion, this study has shown that repeated sprint ability as well as higher anaerobic capability as reflected by the short distance. Keywords: swimming, repeated sprint ability, short distance swimming performance

Is physical fitness related with in-game physical performance? A case study through local positioning system in professional basketball players

The purpose of this study was to investigate the relationship between physical fitness and external load determined by local positioning system (LPS) in a simulated basketball game. Fourteen professional male basketball players performed a lane agility drill, 20-m maximal sprint speed, countermovement jump (CMJ), drop jump, and repeated sprint tests. Player movements during games (two games of 4 × 7 min) were measured using a portable WIMUPRO LPS and six ultra-wideband antennas. Distance covered, and distance covered in different speed zones, accelerations, and decelerations were recorded. The results obtained showed significant relationship between (a) distance at high decelerations (&gt;−2.0 m s−2) and 20-m maximal sprint speed ( r = 0.669, p = 0.049); (b) 20-m maximal sprint speed and maximal speed in simulated games ( r = 0.576, p = 0.031); (c) CMJ height and sprint distance (&gt;24.1 km h−1) covered in simulated games ( r = 0.772, p = 0.001); and (d) high decelerations and 20-m maximal sprint speed ( r = 0.669, p = 0.049) and best time in the RSA test ( r = −0.731, p = 0.039). Coaches and strength and conditioning coaches must adjust their training to optimize speed and jumping ability, as they are reflected in physical performance in-game. Players who reach higher speeds (i.e. RSAbest and 20-m sprint time) and CMJ height in field tests may be affected by greater deceleration load in specific training and competition (eccentric contraction). Since hamstring muscles suffer great strain during deceleration, they are more prone to injury, thus these players may require a specific training program to decrease performance losses and risk of injury.

The Relationship between the Performance of Soccer Players on the Curved Sprint Test, Repeated Sprint Test, and Change-of-Direction Speed Test

The curved sprint test is the most commonly used test in team sports. From a practical point of view, it would be interesting to know to what extent it is related to a direct sprint and a sprint involving changes in direction. This study investigated the relationship between the times taken by soccer players in the curved sprint test, repeated sprint test involving changes in direction, and change-of-direction speed test. Two age groups of soccer players U15 and U17 (n = 22) took the curved sprint test, the repeated straight sprint test, and the repeated straight sprint test involving changes in direction. The total time taken in the curved sprint test did not differ significantly from the total time taken in the repeated straight sprint test (46.80 ± 1.85 s and 34.51 ± 1.66 s, respectively; T = 120). The total time taken in the curved sprint test was not significantly different from the total time taken in the repeated straight sprint test involving changes in direction (46.80 ± 1.85 s and 82.36 ± 4.47 s, respectively; T = 115). There was no significant correlation between the total times taken in the curved sprint test (CST) and the repeated sprint test involving changes in direction (RSCD) (r = 0.180). There was also no significant correlation between the total times taken in the curved sprint test (CST) and the repeated straight sprint test (RSST) (r = 0.301). The non-significant relationship between these abilities implies that they are independent of each other and may have to be tested and trained complementarily.

Effects of Caffeine Supplementation on Physical Performance of Soccer Players: Systematic Review and Meta-Analysis.

Caffeine is 1 of the most popular supplements consumed by athletes, and the evidence for improving soccer performance remains limited. To investigate and update the effects (benefits and harms) of caffeine to improve performance on soccer players. Electronic search in Medline (via PubMed), CENTRAL, Embase, SPORTDiscus, and LILACS, from inception to March 28, 2020. Randomized clinical trials (RCTs) assessing the effects of caffeine on the performance of soccer players. Systematic review with meta-analysis. Level 1. Data extraction was conducted independently by 2 authors using a piloted form. We assessed methodological quality (Cochrane risk-of-bias [RoB] table) and the certainty of the evidence (GRADE [Grading of Recommendations Assessment, Development and Evaluation] approach). Sixteen RCTs were included. Overall methodological quality was classified as unclear to low risk of bias. When assessing aerobic endurance, meta-analyses did not demonstrate the differences between caffeine and placebo (mean difference [MD], 44.9 m; 95% confidence interval [CI], -77.7 to 167.6). Similarly, no difference was observed during time to fatigue test (MD, 169.8 seconds; 95% CI, -71.8 to 411.6). Considering anaerobic power, meta-analyses also did not find differences for vertical jump (MD, 1.01 cm; 95% CI, -0.68 to 2.69) and repeated sprint tests (MD, -0.02 seconds; 95% CI, -0.09 to 0.04), as well as reaction time agility test (MD, 0.02 seconds; 95% CI, -0.01 to 0.04) and rating of perceived exertion (MD, 0.16 points; 95% CI, -0.55 to 0.87). Regarding safety, a few minor adverse events were reported. Based on the GRADE approach, the certainty of this evidence was classified as very low to low. We found no significant improvement in soccer-related performance with caffeine compared with placebo or no intervention. However, caffeine appears to be safe.

The effect of isolated or combined small-sided games and speed endurance training on physical performance parameters in young soccer players

The purpose of this study was to investigate the effects of six weeks of small-sided games (SSG), speed endurance (SER) and combined SSG and SER (CT) training programs on sprint, repeated sprint, Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and level 2 (Yo-Yo IR2) performance in young soccer players. Forty-one elite young soccer players (body height: 174.0 ± 7.5 cm, body weight: 59.7 ± 9.5 kg, age: 14.6 ± 0.5 years, training age: 7.4 ± 0.6 years) underwent anthropometric measurements before performing 10m and 30m sprint tests, repeated sprint tests, and Yo-Yo IR1 and Yo-Yo IR2. The players were then divided into four groups: the SSG group (SSG; n=11), the SER group (SER; n=10), the CT group (CT; n=11), and the control group (CG; n=9). All groups performed training for six weeks on two days out of the five training days the participants were undertaking. There was a statistically significant increase in the Yo-Yo IR1 and Yo-Yo IR2 test performances of players in SSG, SER and CT groups (p&amp;lt;.05). In addition, players in these groups showed significantly higher percentage increases in Yo-Yo IR2 test performance compared to the CG. The CT group also had a statistically significant increase in Yo-Yo IR1 test performance compared to the CG (p&amp;lt;.05). In conclusion, while this study shows that SSG and SER training can be used for physical performance development in isolation or in combination, coaches and sports scientists are advised to choose combined training to use training time more efficiently.

Muscular and Physical Response to an Agility and Repeated Sprint Tests According to the Level of Competition in Futsal Players.

The aim of this study was to evaluate the neuromuscular response to an agility and repeated sprint ability (RSA) test according to the level of competition in futsal players. A total of 33 players from two elite teams and one amateur team participated in the study. The participants completed an agility t-test, a 30 m-speed test, and a RSA test. A countermovement jump (CMJ) test and a tensiomyography test of the rectus femoris (RF) and biceps femoris (BF) of both legs were carried out before and after the tests. RSA test revealed better sprint times in elite players compared to amateurs in the seven bouts, as well as in the 30 m sprint and in the agility test (p < 0.05). Before the tests, elite players showed higher sustain time (Ts) in RF (+31.03 ms; ES: 0.76) and BF (+28.73 ms; ES: 0.73), higher half-relaxation time (Tr) in BF (+20.79 ms; ES: 0.94), and lower delay time (Td) in BF (−2 ms; ES: 1.19) compared to amateur players. However, post-test values did not present any significant differences (p > 0.05). In conclusion, elite players showed greater performance in the RSA test, in the 30 m tests and in the agility test compared to amateur players. The contractile properties were not a key factor in the RSA performance of the futsal players.

Acute Effects of Brief Mindfulness Intervention Coupled with Carbohydrate Ingestion to Re-Energize Soccer Players: A Randomized Crossover Trial.

Background: This field experiment investigated the acute effects of brief mindfulness-based intervention (MBI) coupled with carbohydrate (CHO) intake on players’ recovery from half-time break in a simulated soccer competition. Methods: In a single-blinded randomized crossover experiment, 14 male players received 3 treatments (Control: non-carbohydrate solution + travelling introduction audio; CHO: CHO–electrolyte solution + travelling introduction audio; and CHO_M: CHO–electrolyte solution + MBI) during simulated half-time breaks. Vertical jump, sprint performance, mindfulness level, rate of perceived exertion, muscle pain, mental fatigue, blood glucose, and lactate were measured immediately before, during, and after the exercise. Results: (1) MBI significantly increased participants’ mindfulness level (Control vs. CHO_M, p < 0.01; CHO vs. CHO_M, p < 0.01) and decreased mental fatigue for CHO_M condition (pre vs. post, p < 0.01); (2) participants in the CHO_M condition performed better in the repeated sprint tests than in the Control and CHO condition (Control vs. CHO_M, p = 0.02; CHO vs. CHO_M, p = 0.02). Conclusion: Findings of this study provide preliminary evidence of the positive effect of MBI coupled with CHO ingestion on athletes’ recovery from fatigue in the early stage of the second half of a game.

SPRINT PERFORMANCE IN FOOTBALL (SOCCER) PLAYERS WITH AND WITHOUT A PREVIOUS HAMSTRING STRAIN INJURY: AN EXPLORATIVE CROSS-SECTIONAL STUDY.

Hamstring strain injuries are common in many sports. Following a hamstring injury, deficits in peak and explosive strength may persist after return to sport potentially affecting sprint performance. Assessment of repeated-sprint ability is recognized as an important part of the return to sport evaluation after a hamstring injury.Purpose: This purpose of this exploratory cross-sectional study was to compare sprinting performance obtained during a repeated-sprint test between football players with and without a previous hamstring strain injury. Forty-four fully active sub-elite football players, 11 with a previous hamstring strain injury during the preceding 12 months (cases; mean age, SD: 25.6 ± 4.4) and 33 demographically similar controls (mean age, SD: 23.2 ± 3.7), were included from six clubs. All players underwent a repeated-sprint test, consisting of six 30-meter maximal sprints with 90 seconds of recovery between sprints. Sprint performance was captured using high-speed video-recording and subsequently assessed by a blinded tester to calculate maximal sprint velocity, maximal horizontal force, maximal horizontal power, and mechanical effectiveness. A significant between-group difference was seen in favor of players having a previous hamstring injury over 6 sprints for maximal velocity (mean difference: 0.457 m/s, 95% CI: 0.059-0.849, p = 0.025) and mechanical effectiveness (mean difference: 0.009, 95% CI: 0.001-0.016, p = 0.020). Repeated-sprint performance was not impaired in football players with a previous hamstring strain injury; in fact, higher mean maximal sprinting velocity and better mechanical effectiveness were found in players with compared to without a previous hamstring injury. The higher sprinting velocity, which likely increases biomechanical load on the hamstring muscles, in previously injured players may increase the risk of recurrent injuries. 3b.

Warm-up durations in a hot-dry climate affect thermoregulation, mean power-output and fatigue, but not peak power in specific soccer repeated-sprint ability

BackgroundThis study addressed the lack of data on the effect of warm-up (WU) duration in hot-dry climate (~ 30 °C; ~ 18% RH), on thermoregulation, muscular power-output, and fatigue after specific soccer repeated-sprint test (RSA).MethodsEleven amateur soccer players participated in a cross-over randomized study and they underwent the Bangsbo repeated-sprint test, after three WU durations (i.e. WU10, WU15 and WU20 min) at 70% of MAV, and on different days. Peak power (PP), mean power (MP) and the fatigue index (FI) were recorded and analyzed. Likewise, heart rate (HR), tympanic temperature (Ttym), mean body temperature (MBT) and rating of perceived exertion (RPE) were recorded during each session.ResultsThe repeated measure ANOVA showed that MP improved after WU15 in comparison to WU10 and WU20 (p = 0.04 and p = 0.001; respectively). Nonetheless, no significant effect on PP was recorded after all WU durations. FI during RSA increased after WU20 in comparison to WU15 and WU10 (p < 0.001 and p = 0.003; respectively). Higher RPE values (p < 0.001) were recorded after WU15 and WU20 in comparison to WU10 duration. The two-way ANOVA showed higher ΔTtym and ΔMBT values after WU15 and WU20 compared to WU10 (p = 0.039 and p < 0.001for Ttym; p = 0.005 and p < 0.001 for MBT, respectively).ConclusionsThe WU15 at 70% of MAV better assists mean power-output during soccer RSA in hot-dry (~ 30 °C; 18% RH) climate, but not peak power. Reducing WU duration up to 10 min seems to be insufficient to induce beneficial physiological changes necessary for optimizing repeated-sprint performance, while its extension up to 20 min remains detrimental for muscular power and induces higher fatigue.

Soccer-Specific Reactive Repeated-Sprint Ability in Elite Youth Soccer Players: Maturation Trends and Association With Various Physical Performance Tests.

Di Mascio, M, Ade, J, Musham, C, Girard, O, and Bradley, PS. Soccer-specific reactive repeated-sprint ability in elite youth soccer players: maturation trends and association with various physical performance tests. J Strength Cond Res 34(12): 3538-3545, 2020-Repeated-sprint ability is an important physical prerequisite for competitive soccer and deviates for players in various stages of growth and development. Thus, this study investigated reactive repeated-sprint ability in elite youth soccer players in relation to maturation (age at peak height velocity) and its association with performance of other physical tests. Elite male youth players from an English Premier League academy (U12, n = 8; U13, n = 11; U14, n = 15; U15, n = 6; U16, n = 10; and U18, n = 13) completed the reactive repeated-sprint test (RRST; 8 × 30-m sprints with 30-second active recovery), and other physical tests including the Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2), arrowhead agility test, countermovement jump test with arms (CMJA), in addition to 10- and 20-m straight-line sprints. Reactive repeated-sprint test (RRST) performance (total time across 8 sprints) progressively improved from U12 to U16 (p < 0.01; effect size [ES]: 1.0-1.9), yet with no differences found between U16 and U18. No between-group differences in RRST performance were evident after accounting for age at peak height velocity (p > 0.05; ES: <0.3). Correlation magnitudes between performance on the RRST and other tests were trivial to moderate for the Yo-Yo IR2 (r = -0.15 to 0.42), moderate to very large for the arrowhead agility test (r = 0.48-0.90), moderate to large for CMJA (r = -0.43 to 0.66), and trivial to large for 10- and 20-m sprints (r = 0.05-0.61). The RRST was sensitive at tracking maturation trends in elite youth players, although performance improvements were not as marked from 15 to 16 years of age. RRST performance correlates with several physical qualities decisive for competitive soccer (agility, speed, power, and aerobic endurance).